Electrical Knowledgebase
Since 1984, Gaylor has built its strong reputation on a foundation of quality and safety. Over the years, our experienced team of electrical professionals has developed a wealth of knowledge in the application of high standards of design and engineering to the construction of many complex and high-profile projects. Our electrical knowledgebase is designed to share some of that knowledge. From time to time, we'll post articles that relate to important safety and quality issues in electrical construction.
Current Articles
What are the requirements for panel board labeling?
A panel schedule is required at each panel. Each circuit must be clearly marked to indicate its specific purpose or use and must include enough detail to differentiate it from other circuits. Office lights or warehouse receptacles would not be sufficient information, even in a small facility added circuits in the future would create confusion. A new change in the 2008 code no longer allows circuit descriptions based on “transient conditions of occupancy” such as Jim’s office lights because Jim will not always be the occupant of that office and there will be no way to know what office is being referred to once Jim is gone. Read more...
What are the requirements for installing electrical boxes in fire rated walls?
Per IBC 711.3.2:
1. Steel boxes that do not exceed 16 square inches (4” x 4”) may be installed provided the total area of openings does not exceed 100 square inches for any 100 square feet of wall area. Read more...
What are the cover requirements for installing PVC conduit underground?
Direct-buried cable or conduit or other raceways shall be installed to meet the minimum cover requirements of Table 300.5. Read more...
What are the requirements for installing covers on receptacles in damp and wet locations?
PER NEC 408.8
(A) Damp Locations. A receptacle installed outdoors in a location protected from the weather or in other damp locations shall have an enclosure for the receptacle that is weatherproof when the receptacle is covered (attachment plug cap not inserted and receptacle covers closed). Read more...
What are the requirements for installing EMT conduit or MC cable near a roof deck?
Per NEC 2008
300.4 (E) Cables and Raceways Installed Under Roof Decking. A cable- or raceway-type wiring method, installed in exposed or concealed locations under metal-corrugated sheet roof decking, shall be installed and supported so the nearest outside surface of the cable or raceway is not less than 38 mm (1 in.) from the nearest surface of the roof decking.FPN: Roof decking material is often repaired or replaced after the initial raceway. Read more...
What is the proper procedure to energize and test a newly installed transformer?
Disclaimer
The interpretations expressed here are those of the author and are intended to be a guideline only. They are based on the references listed. It is the responsibility of the reader to be sure this complies with the codes, standards, and specifications applicable to any given situation. Compliance with codes, standards, and specifications is the responsibility of the installer. Final interpretation is up to the local authority having jurisdiction.